External respiration or breathing is a process of inhaling the air into the lungs and expelling the air that contains more carbon-di-oxide from the lungs to the outer environment. Exchange of gases in and out of the blood also takes place simultaneously.
Two paired sheets of muscle from the ribs to the pelvis that flex you forward. Transversus Abdominis. The deepest ab muscle, which wraps around the waist to support the spine. Think of your ab muscles as the meat in the middle of a fat sandwich.On top of them is subcutaneous fat, the stuff you pinch as you look in the mirror.he answer includes factors like body type, fat composition, and possibly even the shape of the pelvic bone, where your ab muscles attach, she says. Theoretically, a wider pelvis can translate into a broad lower abdomen and hips, compared with what's north of the belly button.
[edit on Wikidata] The rectus abdominis muscle, also known as the abdominals or abs, is a paired muscle running vertically on each side of the anterior wall of the human abdomen, as well as that of some other mammals. There are two parallel muscles, separated by a midline band of connective tissue called the linea alba.